Grinding-mill.



E. C. JOHNSUN.

GRINDING MILL.

APPLIoATIoN FILED 001224, 1910.

Patented Feb. 6, 1912.

2 SHEETS-SHEET 1.

E. C. JoHNsoN. GRINDING MILL.

lzazented Feb. 6, 1912.

2 SHEETS-SHEET 2.

'' Milli 'fi p -auml U'NTTED STATE-s PATENT OFFICE.

ERNEST C. JOHNSON, OF HILL CITY, SOUTH DAKOTA.

Specication of Letters Patent.

PatentedFeb. 6,1912.

Application led October 24, 1910. Serial No. 588,763.

mills of that type which comprises aI rotat ing shell or drum containing a number of longitudinally extending grinding members or rods which are adaptedtoreduce or grind material, such as rock or ore, by attrition, to the desired fine-ness and in such manner that the material will be reduced without the necessity of repeatedly treating the same in the mill and withoutseparating the oversize material from the rest which has-passed through the mill and re-grinding the former. One feature of -the invention consists in providing a drum having its lining or internal periphery formed, so that in rotation, the longitudinally extendinggrinding mem bers will be rotated relatively to eachother and rotated in the drum in such manner that the ore, in transit through the drum,owill be quickly reduced to the desired ineness and in which this operation is efficiently and economically effected. By the provision of a slightly undulating or continuously corrugated internal periphery 4in the rotating drum, the loose grinding-members or rods will be caused to rotate relatively to one another and to t-he drum, rendering them more effective as grinders, as distinguished from an intermittent 4elevation and dropping of one of the grinding members upon the others, since constant relative rotation and movement of these grinding-rods will serve more eiiiciently, to bring all portions of the ore between the contacting surfaces thereof, and to reduce them to a mass of substantially uniform ineness.

The invention also designs to increase the eiciency of a grinding mill, by providing' a structure whereby loose longitudinally ex tending grinding-members or rods in the drum will be operated longitudinally or in endwise direction relative to one another.

The invention also provides grinding-rods or members of improved construction whereby it will be rendered durable and whereby likelihood of breakage, resulting from operan tion in loose series in a drum, will be avoided.

The invention further designs to provide a grinding-mill with means for collecting metallic particles, such as gold, which have been separated from the ore by grinding.

` The invention still further designs to pro' vide a grinding-mill of improved construct1on and operation.

The inventionl consists in the several novel features hereinafter set forth and more par-V ticularly defined by 'claims at the conclusion hereof. In the drawings: Figure 1 is a longitudinalsection of amill embodying the invent1on. Fig.. 2 is a transverse section taken on line 2-2of Fig. 1. Fig. '3 is a face view of oneof the drum-heads, showing more particularly the format-ion of the discharge opening for the material and the surface on said head which cause the longitudinally' extending grinding members lto be operated longitudinally in the drum. Fig. 4 is a de- 1Bail perspective of one of the grinding-mem ers.

The improved grinding-mill comprises a rotatable drum 9 which.` is adapted to contain a number of loose longitudinally extending round grinding-rods or members 10 which extend substantially throughout the length of the chamber in the drum and are4 usually suiiioient in Anumber to fill up approximately one-half of said chamber. The drum is formed of an outer shell 11 and a lining 12, which are suitably secured together. The liningis composed of arcuate sectionsl 12a, `and 12? all being similarly wedge-shaped longitudinally so that when the other sections are placed in circular relation in the shell, section 12b may be driven into lace to firmly secure the lining and so that 1t will be self-retained in the shell. It will be understood that while I prefer to form all the sections, including the locking sections 1 2", of exactly the same shape,'I may if desired employ as locking members sections 12b of dierent shape from the other` sections. Longitudinally, the lining is also composed of a number of annular series of sect-ions, so that a complete lining will be built up of a number of annular seriesof sections and this construction adapts the lining-sections, for drums of different lengths and also makes it necessary in event of ex- -acessive wear or breakage of a section to remove and replace only the section or sections affect-ed. .The sections of the drum-lining are usually formed of chilled metal to provide an effective grinding surface and. by

forming the/lining in sections in longitudinal and .arcuate sections, they mayl berreadily chilled and handled.

The inner periphery or operative face of 5 the'drum, being the inner face of the drumlining, is formed with alternating shallow,

depressions and raised portions, or shallow corrugations, to provide a constantly undulating surface; rlhis undulating peripheral surface of the drum will cause, as the drum is rotated, constantrelative displacementof the rods between'one another and will cause constantrelative rot-ation of all of the rods relatively to one another and to the drum, so that the material between the rods will be ground by attrition. Resultantly, the efliciency of the mill is materially 1ncreased by the rollingl or rubbing action of the rods resulting from the rotation or relagatedsurface, and more particularly in the ascending motion of the drum, to produce a most v effective grinding action and furthermore the rods are caused to roll `relatively to, over and between one another lwhich causes a' more efficient pulverization or grinding action than occurs in a machine in which t-he operative periphery is smoothly cylindrical or is equipped with means for periodically causing a rod to be carriedA upwardly with the drum, and then 'dropping it on the heap of grinding-members. The meeting orabutting edges between the sections of each annular vseries openings through which vthe pulverized maf terial will be discharged from the drum.` Each drum-'head 30 comprises a backingplate 3()a and a lining 30". This lininghas one face, being that face which forms the inner facel of the drum-head at the discharge-end of the drum, formed with a se.

ries of radial grooves or channels 31.-' TheY Aback of each groove is inclined or tapered outwardly, as at 32, and the-sides 33 of each channel 31 arealso"tapered. Bolts `V36 ,re'adapted to removably secure the heads to rings 37 which are riveted to the outer ends of the drum respectively, and hinges 50 pivotally connect the drum-heads to rings 37, so that the heads may be conveniently handled' when access to the interiorof the 'drum vis desired. The outer face of each plate 30, being that which vformssthe inner surface of the head when it is secured at tive movement of the undulating or corruthe ingress end of the drum, is substantially flat, so that it will provide a closure bey Aalso increases the grinding eliicien'cy and capacity of the mill. In ascending, the inclined faces of the channels 31 cause the rods lto move longitudinally away from the discharge-end of the drum.

Each drum-head is provided with a cent-ral opening 39 through one of which the material`to be crushed is adapted to be'conducted to the grinding-,chamber in the4 drum, by a hopper 40 suitably secured to a bed or frame A and the opening in the head atv the discharge-,end of the drum is closed by4 a cap 4l, which is removably secured to the head by bolts 42, which permit the cap to be removed when the drumhead is to be employed at the ingress-end of the drum. A

When the machine is to be used for wet grinding withl water, the drum-head at the discharge-end may be reversed so that its flat face will abut against the end 'of the drum to close it around the periphery, and the cap 41 may be removed to cause material to be discharged through the central openlng 3 9 in said head. Hinges 50'are lsuitably formed toy permit this reversal.

It 1s 4desirable that the loose grinding-- rods l0 should have hard rolling surfaces which contact with the material and with the other rodskin the drum, but in practice, 1t hashbeen found that if these rods are formed of uniform density and hardened throughout, they are so brittle that breakage-frequently occurs from the stresses to vwhich they are subjected `in the drum.y To

overcome this objection without lessening the durability of the rods, each is Aformed of a core 10a of soft or wrought metal, such as rolled iron or soft steel,"and a surrounding body 10tr of hardchilled iron or steel 1s Ffused or cast aroundthe core, and thus each rod is given a hard and efficient grindmg surface and rendered less liable to breakage. l Y

A Bed .A which supports the drum is tiltably mounted at its center,'being pivoted, as at 25, in brackets 26`secured lon the oor orssupport upon which thev'mill is to be operated. Suitable means, such as jacks 27 are provided for holding' the bed and drum 5 inclination of the drum 'and reverse the course of the materiall through the drum. The hopper 40 may be connected to either or the elevated end of the druln, and-the reversibility of the drum-heads, makes it possible to discharge the material at either end of the drum.

Rings or bands 13 are secured to the shell 11 ofthe drum and each engages a pair of rollers 14, the rollers of each pair being disposed respectively at opposite sides of the axis of the drum and lnounted in brackets l5, which are adjustably sustained by bed or frame A. This bed supports suitable Vdriving-mechanism for the drum, which comprises a shaft 17 journaled'in bearings 18 on said frame, a pinion 19 secured to said shaft and a driving pulley 20 wherebysaid shaft and pinion may be continuously driven. A gear-ring 21 is secured to the central portion of the drum, being bolted,

as at 22, to a ring 23 riveted to the shell 11.

Said gearing meshes with pinion 19 and causes the drum to rotate when the drivingmechanism is operated. A pair of rollers b, b engage the opposite edges of one of the rings 13 to confine the drum against longitudinal movement relatively to the frame or ,bed A.

The drum-lining is omitted at each end,

35 to provide channels, in which a channeled copper ring 52 is placed. These rings have a coating or lining of quick-silver rubbed thereon, and-may first be plated with silver, if`desired. Metallic particles, such as gold, have a strong aiinity for quicksilver and will amalgamate with it, and resultant-ly the gold particles in the grindings will be retained in these channels, While the remainder of the l ground ore will be discharged through openings 31. At the end of a run, thegold may be removed from ring 52 and asthe amalgam hardens and the gold is col- 1ected, additional quicksilver may be added. In practice, thering 52 at the discharge-end only need be lined with quicksilver, but by providinga ring at each end, either end of the drum may be'used as a discharge-end.:

These collecting channels are disposed outside ofthe grinding-members, so the latter will not disturb the quicksilver or amalgam in rings 52. v

The. operation of the improved mill will be as follows: Assuming the, drum to be in the position illustrated in Fig. 1, that thel material to be reduced is being supplied to the drum through hopper 40 andthatthe drum is being rotated by the driving-mechanism, the ore or other material entering the drum' at the 'highest end thereof, will be caught between the constantly and relatively rotating grinding-rods, which in their rotation will canse the material teo pass between the rods and be conined in the spaces therebetween. 'lhe constant rotation and motion of the rods on and between one another, the relative longitudinal movement of the rods', and the constant movement and rotation of the rods caused by, and relatively to, the undulating or corrugated internal periphery of the drum, together with the confinement of the material between the rods and the weight of the.

mass of rods on the material, will cause the material to be reduced or pulverized and during such treatment, it will progress through the inclined drum and when completely pulverized or reduced, will escape in radial direction through the peripheral discharge openings 31. This construction is one which results in increased capacity and efficiency of the machine and accomplishes this without subjecting the grinding-members to an impact or dropping thereof, and by consumption of little power. The free gold, released lay-grinding, will be collected in the rings 52 and remain there until it is rem oved,l when desired.

The invention thus provides a grindingmill which is eiiicient in operation and which reduces the material to an approximately uniform degree of iineness. The grindingrods, formed of metals of different densities and flexibilities, are durable and have effective wearing surfaces. The drum-heads are reversible to adapt the drum for either dry or wet grinding. In event the drum-head at one end becomes worn, the drum may be discharged at the opposite end from which Arestricted to the details shown and described, since these may be modified within the limits-of the appended claims, without departing from-the spirit and scope of the invention. Y

Having thus described the invention, what I claim as new and desire to secure by Letters Patent, is:

1, A grinding-mill comprising a drum having a continuously undulating interior surface extending from end to end thereof, elongated grinding-rods of a length substantially equal to that of said drum loosely disposed therein in superimposed strata,

said surface being formed to rotate and bodily shift the rods relatively to one ano-ther assaid drum is rotated, and mechanism for rotating said drum.

2. A grindingmill comprising a drum, mechanism for rotating the drum, elongated grinding-rods loosely disposed therein, and means carried'by said drum for causing the grinding-bars to move longitudinally relatively-to one another. v

. 3. A grindingmill comprising a drum having an undulating peripherymechanism for' rotating the drum, elongated grinding rods loosely disposed therein, and l0n the undulatingy periphery, and means carried bysaid drum for causing the rods to move longitudinally relatively toone another.

4. A grinding-mill comprising a drum,

mechanism'for rotating the drum, la Vseries of elongated grinding-rods loosely disposed therein, a head at one end of the drum, and

l means on the head for causing said rods to move longitudinally relatively to one another.

5. A\ grinding-mill comprising a drum, mechanism for rotating the drum, a series of elongated grinding-rods loosely disposed therein, a head at one endf of the drum, and

comprisingv a lining, and means on'the lining for causing said rods to move longitudinally relatively toene another.

6. A grinding-mill comprising fa drum,

mechanism for rotating the drum, a series Y.of elongated grinding-rods loosely disposed therein, and a head at one end of the drum,

saidl head having 'outwardly extending channels therein, and inclined surfaces for shifting the rods longitudinally. n ,s 7. A grinding-mill' `comprising adrum, mechanism for rotating' the drum, a series ofelongated grinding-rods loosely disposed provided with dischargeeopenings forl thel therein, and a head:atxoneV end ofthe with a lining having-outwardly extending .channels therein, and inclined-V surfaces for lshifting Y the rods longitudinally.

8. A grinding-mill lcomprising a drum,

mechanism for rotatingthe drum, a reversimaterial and-its other face being formed to close the end of the drum, and grinding-- members in the drum. AY grinding-mill comprising a: drum, mechanism for rotating the drum, a. reversible drum-head, one of the faces whereof is provided with dischargeopenings for the material and its other face being formed to close the end -of the drum, and grindingmembers in the drum, said head comprising a backing and a lining.

l0. A grinding-mill comprising. a drum,r mechanism for rotatingthe drum, a reversi-l ble drum-head, one of the faces whereof is provided with discharge-openings for: the

material and its other face' being formed to close the end ofl the drum, s'a-idahead'having a centrally disposedopening therein, re-

movablefmeansfor closing ,the central opening, and grinding-members in thefdrum..

11, lAgrinding-millk comprisingia Vdrum-,.- `mechanismfor rotating the drum,.a reversi-V ble drum-head, one of the faces lwhereof is `provided with discharge-openings' for the material and its other face being formed to close the end of the drum, said head having a centrally disposed opening therein, removablemeans for closing the central opening, sa-id head comprising a backing and a lining, and grinding-members in the drum.

412. A-grinding-millcomprising a drum,

mechanism for rotating the dru1n,-a drumhead having a series of discharge-channels in one of its faces, and a central opening therein, means on the head for closing the drumagai-nstf discharge of material through said channels, and a removable cap for closing the central opening.

13. A grinding-mill rod composed of a core and a surrounding peripheral or rinding portion, the latter being formed o hard metal to provide an efficient grinding-surface and the core being of relatively softer metal to prevent breakage.

14C.- A grinding-mill rod composed of a core and a surrounding peripheral or rind y ing portion, the core being formed of nonfrangible metal, and the surrounding p0r' tion being formed of relatively hard metal fused upon the core.

15. A grinding-mill including a drum, and 'a removable sectional lining within the drum, said sections having abutting straight edges, there being longitudinal 'corrugatxons upon the inner faces of the sections, one of said- 'sections being tapered in the'direction of its .length and shiftable longitudinally to bind the remaining sections together.

16. A grinding-mill comprising a revolubledrum, anda head connected to the end of peri heral disthe drum and having radial charge opemngs in one of-.1ts-- aces only,

communicating with the interior of the the drum to directthe contents against either head. 4

19. A grinding-mill comprising a drum, a head aty each end of the drum having peripheral discharge openings therein communicating with the interior of the drum, and

having' a centralv opening therein, removablel means for closing the central opening in onel of--the heads, and means for tilting thedrum to direct the'contents against either head.

20. A grinding-mill comprising a drum, a

iLhead at each end of the drum comprising a thereln communicating with the interior oft the drum, and having a central ope ing therein, removable means for closing the central opening in one of the heads, and means for tilting the drum to direct the contents lagainst either head.

21. I n a grinding-mill, a centrally pivoted bed, a revolublel drum supported upon the platform, a head removablyconnected to each end of the body and having a central y opening, a feed device mounted upon the bed and directing material into one end of the body, means for rotatingthe body, and means for tilting the body to direct the contents thereof against eitherl head.

22. In a grinding-milka centrally pivoted bed, a revoluble drum supported upon the platform, a head removably connected to each end of the body and havingacentral opening, a feed device mountedl upon the b ed and directing material into one end of the body, means rotating the body-in either direction, and means for tilting the body to irectl the contents thereof against either ead.

23. A grinding-mill comprisinga drum y hauling. terminal outlets, grinding-bars, and

inwardly inclined deflect-ors for shifting the bars aXay from the outlets.

24. drum, grlnding-bars, anda head having peripheral' outlet openings, said head having inwardly incl-ined deiiecting portions for shifting the bars away from the outlets.

25. A 'grinding-mill comprising a drum, a

drum-head having outwardly extending discharge openings therein, the drum being provided with a channel at its discharge-end or retaining the particles released from the ore by grinding.

x ERNEST C. JOHNSON.`

Witnesses:

' HILDEN C. PETERSON, FRANK W. BEMM.

30` grindinU-mill including a revoluble 

